I just got a fancy vitamix 5200, and it outputs a lot of sound. I've looked up the various ways to quiet a blender, and they all revolve around towels under the base, placement away from walls, and expensive enclosures.

I know roughly how sound propagation works, so all those makes sense. Couple of ideas:Sound absorbing material (either actual soundproofing foam or a towel) on the walls by the blender. Place a wall to reflect sound away from the person.Find a cheap enclosure that doesn't cost $200. Maybe a glass punch bowl? Would a paper bag work?

Given the decibels that a commercial blender outputs, maybe I should just wear hearing protection.

Operate it only within a vacuum jar, supported upon dampened springs and the power chord left relatively loose.

(At a place I worked there was of course a remarkably large reduction of noise when the lid of an otherwise rather noisy line matrix printer cabinet is properly closed before use. The paper feeds in and out from/to the input/output bins passing through brush-dampened slots in the foam-lined cabinet surrounds (plus similarly protected air-vents) of the rather impressively rapidly-impacting 'comb-headed' printer head and the paper-traction mechanisms. So far as I recall, the foam innards was maybe only a quarter-inch or less in thickness, flush to the sheet steel exterior, and probably some rubber grommits mediating the connection between this advanced skin and the internal mecanism-frame. This may suggest a cabinet approach that would suffice. If the effort to do so is not disproportionate to the reasons behind the attempt. Or just buy such a vacant/emptyable printer cabinet of sufficient size and ensure that it doesn't stifle the mechanism so much that it overheats in regular use?)

Soupspoon wrote:Operate it only within a vacuum jar, supported upon dampened springs and the power chord left relatively loose.

(At a place I worked there was of course a remarkably large reduction of noise when the lid of an otherwise rather noisy line matrix printer cabinet is properly closed before use. The paper feeds in and out from/to the input/output bins passing through brush-dampened slots in the foam-lined cabinet surrounds (plus similarly protected air-vents) of the rather impressively rapidly-impacting 'comb-headed' printer head and the paper-traction mechanisms. So far as I recall, the foam innards was maybe only a quarter-inch or less in thickness, flush to the sheet steel exterior, and probably some rubber grommits mediating the connection between this advanced skin and the internal mecanism-frame. This may suggest a cabinet approach that would suffice. If the effort to do so is not disproportionate to the reasons behind the attempt. Or just buy such a vacant/emptyable printer cabinet of sufficient size and ensure that it doesn't stifle the mechanism so much that it overheats in regular use?)

You need some airflow to keep the motor cool. I think a cheap shortcut would be to tape bubblewrap to a bowl/clear box. Then just hang it over the blender. That will direct all the sound into the towels. Ear plugs should do the rest.

What you really need is a smart blender that can be remote controlled via a phone app while you're sitting a mile away in a bunker.

Have you tried simple $1 earplugs yet? In my experience, they can make quite a difference. Unless your blender is diesel-powered, it might even be enough to reduce the sound to acceptable levels. Try them out before spending more.

Before you spend $200 on soundproofing gear, consider spending $200 on noise-cancelling headphones. Those things are useful for more than just blender operation.

I makes me happy to know that consumers can buy products designed for personal use that are so powerful that the use of ear protection is seriously under consideration.

My initial response is to make a cardboard box that does not have a bottom, and is slightly big enough to contain the blender. Then cut a window in it to access the buttons. If that is not enough, try putting a fold a towel into a square, and putting it under the blender and box. This should not take more than 30 minutes to make, and helps everyone else in the room/ house.

"You are not running off with Cow-Skull Man Dracula Skeletor!" -Socrates

Zohar wrote:Is this a practical question or a theoretical one? Because I wouldn't think two minutes of very loud noise a few times a week would be too troublesome.

Depends on whether the blender is being used to make early-morning breakfast smoothies, I suppose.

Unless stated otherwise, I do not care whether a statement, by itself, constitutes a persuasive political argument. I care whether it's true.---If this post has math that doesn't work for you, use TeX the World for Firefox or Chrome

They sell sheets of commercial vibration dampers made from cork and rubber. You could also try to hang a set of insulated drapes in front of your door. Interior doors pass a lot of noise. You could make a box out of egg crate foam available at Walmart's, cheap. Or simply ask your roommate to defer the use while you're asleep on weekends.

First step, prevent transmission of vibrations directly to other solids. Best way, attach the blender with a stiff connection (like big bolts) to a very massive and stiff foundation. Something so big that it shows no amplitudes of movement, like the concrete foundation of your building.

If this is not possible, you need decoupling. Decoupling means that you put a non-stiff (compliant) stage between the blender and the (still preferably stiff and heavy) foundation. The stage should allow the blender to move at fairly large amplitudes itself (as if it's floating in space), while only transmitting small forces to the foundation, minimising covibration of the foundation. The decouplers also usually have a high damping, but the lack of stiffness is key. Look at those blocks of Morris: the rubber teeth have low stiffness, while the cork dampens. Don't put a whole sheet underneath, that just adds stiffness, use small blocks at corners. Too small might reduce the damping from the cork. Or out the blender on a pillow, same idea.

Next step: transmission through the air. That means a box. A heavy box. Mass is key. Sound is pressure waves, and to move through a wall they have to move the wall, after which the wall moves the air again on the other side. Heavy wall means less amplitude for a given pressure. Put the blender in a stone box. Tiles or bricks or the closest that's socially acceptable, otherwise use MDF as thick as you can get away with. MDF has some damping that makes up tad for its lower density.

Or combine box and decoupler, as a double box. Where the inner box 'floats' in woolly stuff inside a bigger box. Woolly= very compliant and with damping. Pillow stuffing, or just pillows. No hard connections at all between the boxes, and not much open air.

If still desperate, cover the inside of the inner box with sound absorption material (usually some kind of thick, open-cell foam). This dampens reflections, otherwise your box will have some internal resonance modes, or high frequencies might hit a mechnical mode of your box walls.

No holes. Sound is logarithmic, a 1% hole means your box won't do better than -20dB even if it is otherwise perfect. Fuck airflow. Just don't it run for very long. Put an ice bag in or whatever. If you do need airflow, there's tricks with mufflers and bends and what not. But no holes is much much easier.

Now, this box approach also works for doors! Make the kitchen a box. No holes. Heavy door. Staple sound absorption material to the wall. Now shoot your roommate, sell the blender.

...anyway, that solution incurs additional costs. Several square metres of plastic sheeting, enough to cover the floor, walls and perhaps ceiling and some means of sticking it there. Or save on that but ensure the availability of strong detergents and cloths. Consider bringing in your own luminol to double-check your thoroughness, after you think you're finished. Overalls and overshoe covers might be a wise procurement, remembering to always properly shuck and don them as you pass out and back in through the designated threshold.

But, before a lot of that, the other problem you have is partly provided for by your original scenario. You'll need some sharp blades (maybe saw-type, but chopping-type is acceptable if you're comfortable with it) but having substantially recuced the size of any individual piece, you could then just use the blender itself to homogenise everything completely, such that a number of buckets-full (multiple buckets, or one over several trips) are perhaps conveyed to a number of carefully chosen off-site storm-drains, or maybe to speed up the chemical disolution in a separate well ventilated area (that does not need to be so noiseproof, but should not be too olfactarily noticable). Mix in strong bleaching agents, if not going the acid route, to significantly denature any incriminating biological fingerprints. Always check for untouched gallstones, artificial hips, false teeth, etc, and deal with them accordingly.

Next week: Electric toasters and bathtubs - are they practical for dealing with that passive-aggressive Post-It Note situation?

EDIT: the challenge of sound dampening lies in the logarithmic aspect. We're sensitive to sound over a rather wide power band.For a given transmission path and frequency, it's usually straightforward to build a 20 or 30 dB reduction. That's a 100- to a 1000-fold. Trouble is, by that time some other source will have become dominant, one that you might not even have heard before. And you don't get the promised dBs of reduction. The main philosophy is: find dominant sound source, apply cheap simple trick, see if it is still dominant. Repeat for next dominant source. Only add bells and whistles if one source stays stubborn (often a hole).

Egg crate foam and isolation dampers, like I said. In residential high rises they use party walls constructed with two 4 inch stud bays with sound deadening insulation and an air break of about 4 inches between them. That probably varies depending on whatever, codes or local practice. If a building is of concrete construction you can use a stethoscope on the concrete beams and hear noise from 20 stories away. If the floor is of concrete you can isolate the bed from the floor with isolation dampers as well. However you could just wake him or her at odd hours until they understand you need quiet because whatever you build assumes that they will use it.

I have heard anecdotally that in airliners they sometime pipe in through speakers the inverse of whatever cabin noise is present, reducing percieved engine noise, analogous to the effect used in noise cancelling headphones I think.

Is such a thing viable?

On another note - I think the best way to isolate vibrations would be to suspend it from above with a thin cord or wire, rather than placing it on anything.

The box idea assumes you don't have to hold the lid down or keep the button pressed to run it. You could probably remote the switching, pretty much by leaving it switched on and flicking the mains switch at the socket instead. If you can't do that, you've got a problem there in that it's going to be loud until you shut the door of the box.

You can cut down the machine-to-worktop transmission with multiple layers of towel or bubblewrap. What you need to do is provide a messed-up mixture of routes at different densities so the sound waves arrive all broken up and can't bounce the worktop.

I'd probably go with a double-hulled plywood box, with dense rubber instead of 20mm square-section pine for all the joints and polyester teddy bear stuffing packed into the spaces between hulls. The fronts of both hulls can be a thick door, with door hinges on the inside of the outer hull to swing it and silicone around where it meets the fixed parts inside. A simple latch will work fine to hold it. You could make the floor stand on rubber standing on a floor standing on rubber standing on the outer hull to break up sound transmission to the worktop more. Lay out rubber blocks in a chequer pattern between floors and offset the pattern in the next space up. Internal surfaces other than the floor can be lined with foam rubber (z = 4 + sin(x) + sin(y)) thick to bounce sound waves around internally and break them up in the process.

The tile idea has merit because it'd make the inside easier to clean and the outside match the walls. Alternatively, you could draw inspiration from Iran:

p1t1o wrote:On another note - I think the best way to isolate vibrations would be to suspend it from above with a thin cord or wire, rather than placing it on anything.

There are only a couple of ways of reducing noise in a residential environment. Air breaks and isolation dampers. They quite often hang HVAC equipment with allthread with springs. Springs have a damping function, that reduces transfer to the structure through the hangers. This assuming the occupied areas is below you. In cheap sinks they will place a sound deadening foam to make the sink quieter on the bottom of the sink basin. This tends to absorb sound rather than reflect it. This make that sink somewhat quieter. Or he could try this.

p1t1o wrote:On another note - I think the best way to isolate vibrations would be to suspend it from above with a thin cord or wire, rather than placing it on anything.

There are only a couple of ways of reducing noise in a residential environment. Air breaks and isolation dampers. They quite often hang HVAC equipment with allthread with springs. Springs have a damping function, that reduces transfer to the structure through the hangers. This assuming the occupied areas is below you. In cheap sinks they will place a sound deadening foam to make the sink quieter on the bottom of the sink basin. This tends to absorb sound rather than reflect it. This make that sink somewhat quieter. Or he could try this.

This + towels is probably my goal, but those enclosures exceed $100-200 each. Funny enough, that middle blender is the one I have.

Does it need to be transparent? If not, it's very simple to glue together an MDF box. You might even start without a door, just leave out the bottom square, put rubber on the edges, and place it over the blender. You can expand from there if you need better results.

If you do want it transparent, you need thick acrylic or polycarbonate. Get pre-sawed plates from the web, thicker=better,glue them together. But those are easier to mess up than MDF, and pricier.

Find out how long the blender runs in an airtight box before it runs hot. If you need air circulation, than that should become the focus of the concept, because gains in other areas won't matter much.

... build the case fan into the inner hull, low down where it can blow cool air onto the motor unit, have multiple perforations in the top of the other side of the inner hull to let warm air escape, have more holes high up on the "in" side and low down on the "out" side of an intermediate hull, have more holes low down on the "in" side and high up on the "out" side of the outer hull, make sure air can't circulate back around between hulls and mount the whole thing on eight feet (at corners and mid-points of sides) on top of a platform that's mounted on eight feet (one foot one quarter of the way in from each end of each side).

sardia wrote:This + towels is probably my goal, but those enclosures exceed $100-200 each. Funny enough, that middle blender is the one I have.

Lose the towels. The blender would tend to walk around the counter, these housings have suction cup feet and sound deadening foam in the bottom of the housing. It isn't too ugly and in the end, once you factor in your time you will invest more, not less then the selling price by making it. And nothing you do will make it quiet, simply less noisy.

Do a little science and experiment before you spend money though. Identify what is transferring the sound. My first pass would consist of hanging a heavy blanket over the door to your room. Interior doors tend to be thin and you pick up a lot of noise through them. And if you don't share a wall with the kitchen is likely the source of most of the transmission. If you want to build a box start off by trying a cardboard box covered with a towel to see if it reduces the noise enough to invest time and money.

I deal with this problem often, as I make a smoothie for myself every morning and often get up before my girlfriend and/or her girls just (who sleep down the hall from the kitchen) are awake. I usually place two oven mitts under the base to absorb the vibration--although I've used 1 or 2 small folded towels, as well--and I wrap at least one towel around the rest of the device plus a down comforter around that. That has proven highly effective. I can generally even hold a nearly normal volume conversation (i.e., without having to exert noticeable effort to raise my voice) while standing right next to the thing as it crushes and blends two trays of ice, along with the rest of my smoothie ingredients.

Eebster the Great wrote:CJP, I'm not sure how you wrapped the comforter around the entire conversation, but I suspect that your story is no longer useful to sardia.

Lies, my threads are eternally useful. I still have the blender. It's still loud. The temporary solution I found was to kick out my roommates. I really should sneak into the fabrication center at work, and just glue together some plastic panels into an open box.